1. Field of the Invention
The present invention is related to porous materials, and more particularly related to a monolithic substrate of materials containing a multiplicity of opened channels of one dimensional macropore having a mesoporous inner surface.
2. Description of the Prior Art
Porous materials containing meso and macro pores and methods for making the materials are known. The following 14 references including patents, published patent applications and publications are the closest prior art references which are related to the present invention.    1. Jiang, et al., “Template-Directed Preparation of Macroporous Polymers with Oriented and Crystalline arrays of Voids”, J. Am. Chem. Soc. 1999, 121, 11630-11637 (hereafter “the Jiang Publication”);    2. Pine, D. J. And Imhof, A., “Ordered Macroporous materials by Emulsion Templating”, Nature, Vol. 389, 1997, 121, 948-951 (hereafter “the Pine Publication”);    3. U.S. Pat. No. 6,207,098 issued on Mar. 27, 2001 to Nakanishi et al. for “Method for Producing Porous Inorganic materials” (hereafter “the ‘Nakanishi Patent”);    4. Pine, D. J. And Imhof, A., “Uniform Macroporous Ceramics and Plastics by Emulsion Templating”, Adv. Mater. 1998, 10, No. 9, 697-700 (hereafter “Imhof Publication”);    5. Colvin, et al., “Preparation of Macroporous Metal Films from Colloidal Crystals”, J. Am. Chem. Soc. 1999, 121, 7957-7958 (hereafter “the Colvin Publication”);    6. Qi, Kai, et al., “Synthesis of 3-D Ordered Macroporous Silicate Using the Template Formed from Monodispersed Polystyrene Latex”, Chinese Science Bulletin, 2000, Vol. 45, No. 11, P. 992-994 (hereafter “the Qi Publication”);    7. Hsieh, S., and Jorgenson, J., “Preparation and Evaluation of Slurry-Packed Liquid Chromatography Microcolumns with Inner Diamethers from 12 to 33 μm”, Anal. Chem. 1996, 68, 1212-12-17 (hereafter “the Hsieh Publication”);    8. United States Patent Application Publication to Kumakhov, et al. for “Polycapillary Chromatographic Column and method of Its Manufacturing” (hereafter “the Kumakov Patent Application”);    9. U.S. Pat. No. 6,541,539 issued on Apr. 1, 2003 to Yang, P. et al. for “Hierarchically Ordered Porous Oxides” (hereafter “the Yang Patent”);    10. Fan, H. et al., “Self-assembled Aerogel-like Low Dielectric Constant Films”, J. of Non-Crystalline Solids”, 285 (2001), 79-83 (hereafter “the Fan Publication”);    11. Brinker, J., Scherer, G., Sol-Gel Science, The Physics and Chemistry of Sol-Gel Process, Academic Press 1990 (hereafter “the Brinker Publication”);    12. Kim, J., et al. “Structural Design of Mesoporous Silica by Micelle-Packing Control Using Blends of Amphiphilic Back Copolymers”, J. Phys. Chem. B 2002, 106, 2552-2558 (hereafter “the Kim Publication”);    13. Choi, D., et al. “Effect of two-step sol-gel reaction on the measoporpous silica structure”, Journal of Colloid and Interface Science, 261 (2003)127-132 (hereafter “the Choi Publication”); and    14. Zhao, D., et al. “Triblock Copolymer Synthesis of Mesoporous Silica with Periodic 50 to 300 Angstrom Pores” (hereafter “the Zhao Publication”).
The Jiang Publication discloses the preparation of macroporous polymer membranes with regular voids. These materials are made using a colloidal crystal template of silica, microspheres, wherein use of the silica microspheres as templates makes it possible to employ a chemical method instead of a thermal method for template removal. For this reason, polymers as diverse as polyurethane and polystyrene can be used to create free standing macroporous films having a well formed porous structure consisting of voids ranging in diameter from 200 to 400 nm. These large cavities are not isolated, but rather interconnected by a network of monodispersed smaller pores having a diameter between 50 to 130 nm.
The Pine Publication discloses a new method for producing highly monodispersed macroporous materials with pore size ranging from 50 nm to several micrometers. The method starts with an emulsion of equally sized droplets to form macroporous materials of titania, silica and zirconia, wherein the emulsion droplets are employed as templates around which material is deposited through a sol-gel process. Subsequent drying and heat treatment yields solid materials with spherical pores left behind by the emulsion droplets, wherein the pore sizes can be accurately controlled.
The Nakanishi Patent discloses a process for producing inorganic porous materials, mainly composed of glass or glass-ceramic components. The components have interconnected continuous three dimensional macropores with a median diameter larger than 0.1 um, and mesopores in the walls of said macropores, wherein the mesopores have a median diameter between 2 and 100 nm. The process can include dissolving a water-soluble polymer or some other pore forming agent and a precursor for a matrix dissolving agent in a medium for mixing with a metalorganic compound.
The Imhof Publication discloses a new method for producing macroporous materials with highly uniform pores in the range from 50 nm to 10 um. The technique can also produce materials of any desired porosity up to approximately 90%.
The Colvin Publication discloses a developed template-directed synthesis to the formation of porous metals. These metals are three-dimensional highly ordered, free standing macroporous metal films with interconnected spherical voids having sizes ranging from about 200 nm to about 400.
The Qi Publication discloses a modified fast sol-gel process, which is based on the template formed from monodispersed polystyrene latex. The process is used for synthesizing a three-dimensional ordered macroporous silica material after removing the template by calcination at high temperature, wherein the silica material contains highly ordered packed pores which are interconnected.
The Hsieh Publication discloses fused silica capillary liquid chromatographic columns with an inner diameter about 12 micrometers to about 33 micrometers. It discloses that there is a linear decrease of the eddy diffusion term as the column diameter decreases, wherein the decreased eddy diffusion term is the predominant fact for achieving a lower height of theoretical plates of the columns.
The Kumakhov Patent application discloses invented polycapillary chromatographic columns with channels having submicron cross-section sizes. The channels' number can be increased up to hundreds of thousands and more with corresponding substantial increase of efficiency, which is due to an increase in a total surface of the walls of the channels. However, the mesopores (if any) of the Kumakhov invention are expelled throughout the substrate which is in a softened condition. Therefore, the inner surface of the channels do not have mesoporous characteristics.
The Yang Patent discloses a low-cost and an efficient method of preparing hierarchically ordered structures by combining, concurrently or sequentially, micromolding, latex templating, and cooperative self-assembly of hydrolyzed inorganic species and amphiphilic block copolymers.
The Fan Publication discloses a process to obtain a series of new spin-on nanoporous silica films with controlled porosity and dielectric constants after evaporating induced self-assembly during spin-coating.
The Brinker Publication discloses the science of sol-gel techniques including processes to manufacture the sol-gel.
The Kim publication discloses formation of mesoporous silica materials using blends of diblock and Pluronic triblock amphiphilic block copolymers as the structure-directing agent and sodium silicate as the silica source.
The Choi Publication discloses the effect of a two-step sol-gel reaction by abrup pH change on the SBA-15 and mesocellular silica foams.
Finally, the Zhao Publication discloses an application of amphiphilic triblock copolymers to direct the organization of polymering silica species, which results in the preparation of well-ordered hexagonal mesoporous silica structure (SBA-15) with uniform pore size up to approximately 300 angstrom.
There is a significant need to provide a monolithic substrate of materials containing a multiplicity of open channels of one dimensional macropore having a mesoporous inner surface extending through the substrate to significantly improve application of the substrate including the application in modern column chromatography.